Radioactive elements, such as rubidium-87 (but not strontium-86 or strontium-87), decay over time.By evaluating the concentrations of all of these isotopes in a rock sample, scientists can determine what its original make-up of strontium and rubidium were.Specifically, rocks gathered from recently erupted Mt.Ngauruhoe in New Zealand gave isochron dates of between 270,000 years and 3.9 billion years—from rocks known to be less than 60 years old! Models, no matter how elegant their mathematics, are only as good as their assumptions and how well they reproduce reality through observation and experimental data.Clearly, such huge time periods cannot be fitted into the Bible without compromising what the Bible says about the goodness of God and the origin of sin, death and suffering—the reason Jesus came into the world (See Six Days? He said, This only makes sense with a time-line beginning with the creation week thousands of years ago.It makes no sense at all if man appeared at the end of billions of years.
Obviously, this works only for things which were once living.
Levels of carbon-14 become difficult to measure and compare after about 50,000 years (between 8 and 9 half lives; where 1% of the original carbon-14 would remain undecayed).
The question should be whether or not carbon-14 can be used to date any artifacts at all? There are a few categories of artifacts that can be dated using carbon-14; however, they cannot be more 50,000 years old.
Then, by assessing the isotope concentrations of rubidium and strontium, scientists can back-calculate to determine when the rock was formed.
The three isotopes mentioned can be used for dating rock formations and meteorites; the method typically works best on igneous rocks. The data from radioisotope analysis tends to be somewhat scattered.